My Lords, we have not yet received an invitation to the conference in Mexico on the humanitarian impact of nuclear weapons and have not yet made a decision on whether the UK will attend. We continue to have concerns that the initiative would divert attention from the 2010 action plan agreed by states parties to the Nuclear Non-Proliferation Treaty.

My Lords, I thank my noble friend for his reply, which is a little more positive than I had feared in that at least it is not a negative. Does he see a problem in that, on the one hand, last April the Prime Minister claimed that Britain had taken the lead in pushing for progress towards multilateral disarmament while, on the other hand, we have not taken part in the UN open-ended working group that was set up to try to overcome the 17-year impasse on the Conference on Disarmament, and yesterday, in the UN General Assembly, the UK voted against resolution L34 to take forward multilateral nuclear disarmament negotiations—which are exactly the sort of negotiations the Prime Minister called for last April? How does he think that the rest of the world is viewing us?

As regards attendance at a conference that is still four months away, British officials have had conversations in Mexico City, Geneva and New York about whether we may attend. It remains very much an open question. Perhaps I may simply say to the noble Baroness that there are a great many different, and in some ways conflicting, bodies in which disarmament is now being discussed. These include the Nuclear Security Summit which will meet again in 2014, the UN Disarmament Commission and the Conference on Disarmament. There have also been a number of discussions on nuclear-weapon-free zones. The question of where one puts the priority and where you think it is most worthwhile to push for development is difficult We hold that the NPT review conference of 2015 should remain one of our priorities. We also think that there is value in the P5 process, on which Britain has been one of the leaders, and in the P5-plus process in which the P5 members discuss these issues with India and Pakistan.

My Lords, do the Government agree with the principal conclusion of the Oslo conference that no state and no international organisation has the capability to address the consequences of the explosion of a nuclear weapon and, much more worryingly, the view supported by experts that it might not be possible to develop such capacities? I hope that the Government disagree. If they do, where is the evidence that we have such capabilities?

My Lords, the valuable contribution that the Norwegians and others have been making on this whole question of the humanitarian and, incidentally, climatic consequences of the explosion of a nuclear weapon are very much something that the UK Government are taking seriously. We see this as a very useful expert contribution. Looking at how, if there were to be—heaven forfend—a nuclear explosion, we would cope as an international community with the consequences, is something that is very valuable to take forward.

Does my noble friend agree that there was very substantial political support for the United Nations resolution on working on methods of dealing with nuclear disarmament, and in particular that although half of the NATO members voted in favour of that resolution, the United Kingdom and the P5, with the exception of China, all voted against it? Perhaps I may remind him that the United Kingdom has established a substantial record—perhaps the leading record among the P5—for work on specific actions such as the verification principle that has given us a great reputation on this issue. We might put that at risk if we do not recognise the strength of the pressures from not only the United Nations but many of our allies in this respect.

My Lords, this is an extremely serious area of international security that we take very seriously. We are worried about some of these conferences where it is easier to pass resolutions than to accept that we need, for example, to control: the storage of fissile materials; the creation of additional fissile material; and the potential trade in fissile material. This is what the currently blocked fissile material cut-off treaty is about, and what the nuclear security summit next year will also be concerned with.

My Lords, will the Minister be able to say what attitude the US Government are taking to attending the Mexico conference? Could it possibly be that we are just waiting to see which way they jump? If so, is that the best way to approach this matter?

My Lords, the United States has also not yet taken a decision. My understanding is that the other members of the P5 are unlikely to attend. I suspect that the considerations of the US Administration may not be totally dissimilar from those that are concerning the British Government.